Up to now, volume data in time phases is obtained by contrast-imaging and then continuously photographing various organs of an object using an image diagnostic apparatus such as an X-ray computed tomography (CT) apparatus, a magnetic resonance imaging (MRI) apparatus, and a nuclear medicine diagnostic apparatus, and a perfusion analysis on a blood flow is performed on the basis of the obtained volume data in the time phases. A conventional perfusion analysis is performed using data obtained by injecting a contrast medium or a tracer into an object. Such a perfusion analysis enables observation of a blood flow dynamic state.
A color map is used in many cases as a method of displaying results of a perfusion analysis. Observation using the color map is actively used to diagnose a blood flow dynamic state and an ischemia site.
In a case where a perfusion analysis is performed on the basis of volume data in time phases, a method of setting a region of interest (ROI) to a dominance region of each main blood vessel and obtaining an average value of blood flow rates is adoptable.
Unfortunately, according to the conventional color map as a method of displaying results of a perfusion analysis, a blood vessel image cannot be displayed for each dominance region, and a blood vessel image of a region corresponding to a dominance region desired to be observed cannot be presented. Accordingly, it is difficult for an operator to visually recognize a blood flow dynamic state when ischemia occurs. Moreover, according the method of setting a ROI to a dominance region of each main blood vessel, there is no choice but to randomly set a ROI concerning the dominance region of each main blood vessel on an image. Accordingly, an average value of blood flow rates obtained for the dominance region of each main blood vessel is not accurate and is low in precision.